Are radiation-induced cavernomas relevant findings? - Results from long-term follow-up with brain magnetic resonance imaging of childhood cancer survivors

Abstract

Introduction: Radiation-induced cavernomas (RIC) after cranial radiotherapy (CR) have an unknown risk of hemorrhage. Zabramski magnetic resonance imaging (MRI) classification is touted as being able to indicate non-radiation-induced cavernomas hemorrhage risk. Based on brain MRI examinations, our aim was to assess the hemorrhage risk of RIC during long-term follow-up (LTFU) of childhood cancer survivors (CCS).

Patients and methods: We analyzed retrospectively LTFU data of 36 CCS after initial diagnosis with acute leukemia (n=18) or brain tumor (n=18), all treated with CR. Detected RIC in LTFU brain MRI (1.5 or 3 Tesla) were classified following the Zabramski MRI classification and were categorized into “high” (Zabramski type I, II or V) or “low” (type III or IV) risk of hemorrhage.

Results: 18 patients (50%) showed RIC with a significant relation to the original tumor entity (p=0.023) and the cumulative radiation dose to the brain (p=0.016): all 9 CCS diagnosed with medulloblastoma developed RIC. We classified RIC in only 3/36 CCS (8%) (1 patient with acute lymphoblastic leukemia (Zabramski type II) and 2 patients with medulloblastoma (type I and type II)) as high risk for hemorrhage, the remaining RIC were classified as Zabramski type IV with low risk for hemorrhage.

Conclusion: RIC are common late effects in CCS treated with CR affecting half of these patients. However, only a few RIC (occurring in 8% of all reviewed CCS) were classified as high risk for hemorrhage. Thus, we conclude that RIC are low-risk findings in brain MRI and the course is mainly benign.